Combustible and/or explosive materials requiring protection from high temperatures and/or open flames are generally either (a) coated with a layer of heat and/or fire protection material, (b) contained within rooms, receptacles, cases or boxes which are made from a heat/fire protective material or (c) sandwiched between multi-layered construction materials containing at least one layer of a heat/fire protective material.
Fire and heat protective materials of the ablative type are generally designed for one-time use. Examples of applications include, coatings for stationary receptacles containing fuel or other combustible substances, coatings for fuel tanks, and the like. Additional applications include protective coatings for stationary storage facilities for explosives and ammunition, as well as coatings for mobile storage facilities for ammunitions carried by planes, helicopters, ships, launches, tanks, and the like. Heat/fire ablative materials may also be applied to safes, lockers, warehouses, storerooms, and the like.
The aforementioned are merely some of the possible applications of heat/fire protective materials.
There are, however, inherent shortcomings with many of the currently existing ablative-type protective materials. Those shortcomings include:
(a) Limited Protection Time. The phrase "protection time" refers to the time needed to heat a material from its normal temperature to a certain threshold temperature, under the influence of a flame and/or heat. A material's protection time is generally measured in terms of hours and/or minutes. PA0 (b) Limited Longevity. The term "longevity" refers to a material's ability to resist oxidative decomposition. A material's longevity is generally measured in terms of years. PA0 (c) Limited Utility. The term "utility" refers to the variety of forms in which the ablative-type materials my be utilized without significantly decreasing their heat/fire protective properties. Typically, such variety of forms include, putties, formable masses, and the like. PA0 (d) High Levels of Toxic Emissions. The phrase "high levels of toxic emissions" refers to (1) the emission of highly toxic fumes and/or (2) the emissions of large amounts of toxic fumes. These toxic emissions result when the ablative-type protective materials are being burned. PA0 (1) it must be able to protect against high temperatures and/or open flames for a satisfactory period of time; PA0 (2) it must not oxidatively decompose and/or lose its protective properties over a long period of time, often extending many years; and PA0 (3) it must not emit large amounts of, and/or extremely hazardous, toxic fumes when subjected to extreme temperatures and/or open flames. PA0 (a) a polymeric compound comprising a plurality of at least a first repeat unit having the formula ##STR2## wherein the first repeat unit is present in an amount ranging from about 70 to about 100 mole percent, inclusive and PA0 (b) an aluminum sulfate hydrate of the general formula EQU Al.sub.2 (SO.sub.4).sub.3 .multidot.nH.sub.2 O PA0 wherein n is an integer from 14 through 18, inclusive, and wherein the aluminum sulfate hydrate is present in an amount greater than about 50% by weight of the material.
Many attempts have been made to produce a heat/fire protective material which resolves some of the aforementioned shortcomings. For example, in U.S. Pat. No. 4,122,059, heat/fire protective mixtures are disclosed which employ the use of hydraulic cements. Specifically, the fire retardency characteristic of these compositions is accomplished by the use of an inorganic salt hydrate (e.g., aluminum sulfate hydrate and ferrous sulfate hydrate) together with a hydraulic cement (e.g., Portland cement). According to the patent, the cement acts as a moisture stabilizer which absorbs water released from the hydrate and converts the resulting mass into a cement.
Moreover, U.S. Pat. No. 4,462,831 discloses a heat/fire protective material wherein organic binders are mixed with a filler consisting of aluminum sulfate hydrate. The aluminum sulfate hydrate is present in an amount greater than 70% by weight of the mixture. The organic binders include unsaturated polyester resin, natural rubber, urea formaldehyde, polypropylene, polyvinyl chloride and blends of polyvinyl chloride and polyester.
These binder materials suffer from certain drawbacks. For example, unsaturated polyester and urea-formaldehyde resins are toxic materials. As such, they emit extremely hazardous fumes when burned. Moreover, polypropylene is not sufficiently durable and/or flexible. Therefore, it use is virtually limited to the insulation of planar surfaces. Also, natural rubber does not satisfactorily resist oxidative degeneration. While these binder materials have associated herewith satisfactory heat protection times, they cannot withstand prolonged contact to an open flame. They readily oxidize when exposed to ambient whether conditions.
In order for a heat/fire protective material to be commercially usable,
Other important characteristics which, while not critical, are, nevertheless, extremely desirable, are the material's ability to be employed in many different forms (e.g., as a putty, as a coating, as a protective sheet, etc.) without significantly sacrificing any of the aforementioned necessary heat/fire protective characteristics.
Accordingly, one object of the invention is to provide a heat/fire protective material which retains many of the aforementioned necessary and desired characteristics.
Other aspects, concepts and objects of this invention will become apparent from the following Detailed Description and appended claims.